1. Field of the Invention
The present invention is directed to a seal positioning assembly comprising an expander structure movable relative to a seal, that is primarily, but not exclusively, structured for use with a trocar assembly through which a medical instrument is passed during a surgical procedure. The expander structure is selectively positioned into a seal open orientation so as to dispose the seal substantially out of contact with a medical instrument or so as to accomplish rapid desufflation of a patient's inflated body cavity. In one or more preferred embodiments, the present invention may include a biasing assembly structured and disposed to bias the seal into a closed orientation when a medical instrument has been removed from or is otherwise not present within the trocar assembly.
2. Description of the Related Art
In recent years, the practice of laparoscopy for carrying out endoscopic surgical procedures has replaced major, invasive surgery in a variety of situations. Previously, routine surgical operations were performed by the physician making a large incision into an intended portion of a user's body in order to reach the targeted organ(s) and/or other body tissue. While the size of such major incisions would vary dependant upon the type of surgery needed, it was common-place for the incision to be extensive in order to provide adequate access to the interior body portions of the patient. Upon completion of the surgical procedure, the incision would be closed using conventional techniques. However, it was universally recognized that surgical procedures involving such extensive incisions resulted in significant trauma as well as prolonged recovery periods. In addition, the pain or discomfort endured by the patient, as well as the lack of mobility during such extended periods of recovery, were serious problems.
Because of such disadvantages, new procedures and instruments utilized with the aforementioned laprascopic and/or endoscopic surgery have continued to evolve, such that these new, less invasive surgical techniques have become commonplace. In practice, one or more small openings are formed in the wall of the body cavity utilizing specifically designed penetrating instruments. Medical instruments designed to form the openings are structured to provide physical and visual access into the body cavity being treated. Representative medical instruments used in this type of surgery are generically referred to as a “trocar” or trocar assembly.
Typically, the trocar assembly includes a trocar body having a housing and an elongated sleeve or cannula defining an equally elongated channel or lumen on the interior thereof. In the initial formation of the entrance openings in the patient's body, an obturator is passed through the interior of the trocar by entering the housing portion at one end and passing along the entire length of the interior of the cannula. In most cases, the obturator includes a sharply pointed or appropriately structured tip which facilitates penetration of the exterior wall of the body cavity.
In order to assure that the medical personnel have adequate space for performing the intended surgical procedures, the body cavity is then typically inflated with an insufflation gas to maintain the cavity in a distended state. The insufflation gas is supplied through the interior of the trocar assembly by means of a gas inlet port associated therewith. In addition, the use of one or more valves or seals are provided within the housing portion of the trocar assembly for purposes of preventing the insufflation gas from escaping from the body cavity back through the interior of the trocar assembly. Maintaining the body cavity in an expanded or distended state is, of course, important to the efficient performance of many of the intended surgical procedures. Accordingly, various advancements have been made in the area of valves and seals associated with the trocar assembly in order to eliminate or significantly restrict the escape of the insufflation gas. Therefore, depending at least in part on the structure of the trocar, the type of instruments used in the laprascopic procedures and the intended surgical procedures to be performed, the structural modification of such valves and/or seals vary significantly from one another.
In spite of the availability of a wide variety of valve and/or seal structures, one commonly used structure incorporates what may be referred to as a “duckbill” configuration. The duckbill seal or valve typically comprises an interior channel through which an instrument passes while being inserted through and withdrawn from the interior of the trocar, relative to the body cavity involved in the surgical site. In addition, duckbill valves or seals normally are formed from a flexible material and include two or more converging flap structures having correspondingly disposed distal ends cooperatively positioned and collectively defining a valve opening, wherein the flap structures normally assume a closed position. The insertion of a medical instrument into the housing of the trocar assembly will result in the instrument passing axially through the duckbill valve and through the seal opening thereof by separating the distal ends of the converging flaps.
Further, when an instrument extends through the duckbill valve, the distal ends of the converging flap structures normally engage the outer surfaces of the instrument, but do not form a fluid tight seal therewith. However, one distinct advantage of using a duckbill valve or seal comprises its ability to prevent escape of insuflation gas from the body cavity, through the trocar, before a medical instrument has passed through the duckbill valve or after it has been removed there from. As set forth above, the converging flap structures of a duckbill valve are structured to normally assume a closed, sealed orientation when a medical instrument is absent there from. Therefore, if a medical instrument is not present in the trocar, insuflation gas passing into the trocar from the body cavity is normally prevented from escaping through the duckbill valve. Therefore, venting of the body cavity may typically occur by opening a stopcock or like venting structure on the trocar.
However, the extensive use of duckbill valves or seals has brought to light certain disadvantages associated therewith. These disadvantages include the existence of at least some frictional force exerted on the converging flap structures due to their sliding engagement with the instrument. These forces can tend to at least somewhat inhibit insertion or removal of the instrument and in some extreme cases, may cause the converging flaps to become inverted as the instrument is withdrawn from the interior of the trocar assembly. Another disadvantage involves the problem of the converging flaps of the duckbill valve having a tendency to interfere with and possibly dislodge any anatomical tissue sample attached to and carried by the distal end of the laprascopic instrument, as it is being removed from the trocar. That is, the use of laprascopic and/or endoscopic surgical techniques to obtain tissue samples of organs or other bodily tissue is universally recognized as a preferred alternative to major invasive surgery for the reasons set forth above. Accordingly, reliability in retrieving any tissue samples that are collected during a procedure is important.
Yet another disadvantage of the duckbill valve involves the loss of elastic memory which sometimes results when the medical instrument is repeatedly inserted in and removed from the trocar while passing through the duckbill valve. Alternatively, elastic memory loss can occur if the medical instrument remains in place on the interior of the trocar and through the duckbill valve for an extended period of time. In either situation, the material from which the converging flap structures are formed may partially lose elastic memory at least to the extent of preventing the distal ends thereof from completely closing into the normally sealed orientation. The failure of the flap structures to completely close may result in an unwanted and inadvertent venting of the insufflation gas upon removal of the instrument from the trocar. In addition, the aforementioned loss of elastic memory and the at least partial separation of the distal ends of the flap structures may cause a continuous or periodic “flapping” of the distal ends and a resulting noise, such as a “humming” sound, which is undesirable during the surgical procedure being undertaken.
In attempting to overcome the above-noted disadvantages associated with the use of the duckbill and other types of valves or seals, attempts have been made to develop devices or structures which are operative to dilate a seal or valve into a position that is out of engagement with the instrument passing through the trocar. More specifically, such devices are intended to facilitate the insertion, and in particular, the removal of medical instruments from the interior of the trocar, which are axially positioned relative to a valve or seal associated with the trocar.
It is to be understood that axial movement of the instrument may be made easier by reducing or eliminating the contact between the seal and the exterior surface of the instrument, as well as the distal tip thereof, as the instrument is being withdrawn from the trocar. However, the structural development and implementation of such a seal opening assembly is made more difficult due to the fact that a wide variety of seals or valves, other than a duckbill valve, are commonly used with the many different types of trocars presently available.
Therefore, there is a long recognized need in the medical field for a seal positioning assembly which is structured to selectively open and close a valve or seal regardless of its structure in order to overcome the recognized disadvantages associated with a duckbill valve or seal. If any such improved seal positioning assembly were developed it should have the structural and functional versatility to be used with a large number of different types of seals or valves, other than the specifically described duckbill valve, thereby rendering it useable with a variety of different types of trocar assemblies or other instrumentation associated with laprascopic or endoscopic surgical procedures. Also, if any such improved seal positioning assembly were developed, it should be structured to be operable in an efficient manner by the physician or medical personnel involved in the surgical procedure, without interfering with the technique normally practiced by the physician during the use of the trocar assembly. Also, the structural and functional features of any such improved assembly should be such as to allow selective positioning of a seal between a seal open orientation and a seal closed orientation in order to accommodate a variety of differently sized medical instruments, while reducing or eliminating the frictional engagement between a valve or seal structure and the instrument, as well as facilitating the removal of anatomical tissue from the body cavity and from the interior of the trocar assembly, as the instrument is withdrawn there from. Finally, if any such improved seal positioning assembly were developed, it would ideally also be capable of overcoming problems associated with duckbill valves or like sealing structures relating to the loss of elastic memory, by generally assuring that the converging flaps or other sealing structures will assume a completely closed and sealed orientation, once a medical instrument has been removed from the trocar assembly and/or sealing valve.